Cow Power

Transforming Greenhouse Gases to Renewable Energy

photo of farmer and cow

California dairy farmer John Fiscalini poses in front of his methane digester that converts cow manure into electricity.

Converting cow manure into renewable energy prevents harmful methane from reaching the atmosphere. This is important because methane on dairy farms accounts for the majority of agriculture's greenhouse gas emissions. If methane digesters were installed on most California dairies, they would protect the climate as much as taking more than one million cars off the road - about 5% of the state's total.

The good news is that methane from dairy manure can be captured and converted into energy using existing technologies. The resulting biogas can be used to create:

  • Renewable electricity;
  • Renewable vehicle fuel (biomethane); or
  • Renewable natural gas that can be can be injected into existing pipelines for a wide range of uses (heating, power plants).

Electricity from methane digesters on dairy farms can be used on site (thereby reducing the farmer's energy costs), and the surplus can be sold to a public or private utility. The electricity can replace some power from fossil-fuel plants, which account for approximately 20% of California's greenhouse gas emissions.

The biogas from methane digesters can be refined to produce vehicle fuel, known as biomethane or "cow power." The manure on California dairies could produce enough biomethane to power more than 100,000 vehicles. Dairy digesters can also reduce the risk of excess manure nutrients polluting waterways, including groundwater.

Our Role

Sustainable Conservation has cleared the path for methane digesters on California dairies and made them more economically attractive. Our work in partnership with the dairy industry has brought more than a dozen methane digesters into operation, plus many others under development. We have:

  • Made funding available to reduce farmers' up-front costs;
  • Enabled California dairies to sell electricity profitably;
  • Shaped the first livestock protocol to reward dairy farmers for destroying methane in digesters;
  • Identified innovative technologies that reduce air pollution;
  • Removed regulatory barriers and encouraged more dairy farmers to install digesters.

Sustainable Conservation was a catalyst and guide for putting the first "cow-powered" truck on the road in California's Central Valley. We:

  • Wrote the definitive report on the potential for biomethane as a vehicle fuel;
  • Built an effective partnership to launch the first project;
  • Secured funding to convert the diesel truck to compressed, renewable "natural gas" (biomethane);
  • Educated farmers and policymakers about the project's success.

Our partners in launching the nation's first cow-powered truck:

How It Works

  • Manure is collected in large tanks or storage ponds.
  • Methane is trapped and transformed into biogas.
  • The resulting biogas is combusted to generate electricity or refined further to produce biomethane, a fuel comparable to natural gas.
  • The remaining solid matter is a valuable soil amendment, and the liquids become an easily applied fertilizer with plant-available nutrients and low pathogen levels.